MXPA05009376A

MXPA05009376A - Process for the manufacture of blocked mercaptosilanes.

Info

Publication number: MXPA05009376A
Application number: MXPA05009376A
Authority: MX
Inventors: L Simandan Tiberin
Original assignee: Gen Electric
Priority date: 2003-03-03
Filing date: 2004-03-03
Publication date: 2005-12-05
Also published as: WO2004078813A2; CN100422192C; CL2004000421A1; RU2005130488A; EP1603925A2; JP2006519864A; TW200500371A; AR043461A1; TWI364425B; CA2517875A1; RS20050678A; KR20050107596A; JP4571125B2; BRPI0408662B1; CN1784412A; ZA200507438B; KR101052958B1; NO20054516L; BRPI0408662A; AU2004217886A1

Abstract

A process for the manufacture of a blocked mercaptosilane comprising: reacting at least one polysulfane-containing organosilicon compound of the general formula: (R13SiG)2Sn (a) in which each R1 is independently methoxy, ethoxy or alkyl of from 1 to about 6 carbon atoms, provided, that at least one R1 group is methoxy or ethoxy, G is an alkylene group of from 1 to about 12 carbon atoms and n is from 2 to about 8, with at least one alkali metal, alkaline earth metal or a basic derivative of an alkali metal or alkaline earth metal to provide the corresponding metal salt of the polysulfane-containing organosilicon compound and; (b) reacting the metal salt of the polysulfane-containing organosilicon compound with an acyl halide or carbonyl dihalide to provide a blocked mercaptosilane.

Description

PROCEDURE FOR THE MANUFACTURE OF BLOCKED MERCAPTQSILANS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a process for the preparation of a blocked mercaptosilane, from a metal salt of an organic silicon compound containing polysulfane and an acyl halide or carbonyl dihalide, wherein the metal salt of the organic silicon compound containing polysulfane is formed by reacting an organosilicon containing polysulfane and an alkali metal, alkaline earth metal or a strong base derived from an alkali metal or alkaline earth metal. This invention also relates to the use of said blocked mercaptosilane as a coupling agent in rubber blends. 2. Description of Related Art Sulfur-containing organosilicon compounds are useful as essential components in the production of silica-filled wheels. A tire filled with silica provides enhanced performance in automotive applications, specifically, improved abrasion resistance, rolling resistance and wet skid properties. There is a wide range of organosilicon compounds containing sulfur which are used as coupling agents in silica filled tires. Mercapto-containing organosilicon compounds offer superior coupling at reduced loading, however, their chemical reactivity with organic polymers results in unacceptably high viscosities during processing and premature curing. It has been shown that the blocked mercaptosilanes maintain the benefits of organosilicon compounds containing mercapto without exhibiting the problems noted above. Organosilicon compounds containing blocked mercapto, in particular thiocarboxylic containing silicon compounds, can be prepared by reacting a mercapto-containing silicon compound with an acid halide. The by-product of this reaction, hydrogen chloride, reacts with the organosilicon compound by degrading the desired product and generating chlorosilanes. These reactions with hydrogen chloride are very rapid and can not be prevented by conventional mechanical means, i.e. temperature or pressure, due to the high solubility of the hydrogen chloride in the product. The neutralization of the chlorosilanes noted above can be done using a base such as sodium alkoxide, or propylene oxide, but degradation of the product and / or an undesirable mixture is obtained by making this approach undesirable. Another process previously used is to neutralize the hydrogen chloride, in situ, using an acid acceptor, ie, tertiary amine, see the provisional US patent application no. 60 / 423,577 filed on November 4, 2002; but this requires a stoichiometric amount of the amine that reduces the batch yield and gives a large amount of an undesirable salt that must be removed subsequently, see U.S. Pat. no. 6,229,036. As is known, tertiary amine salts are difficult to remove due to their solubility and conventional filtration methods are mechanically intense and often lead to poor yields. In addition, further processing of the filter cake adds additional costs, such as the disposition of the tertiary amine and the hydrogen chloride salt itself, which possesses significant environmental sequelae.

As shown, the reaction of a metal salt of an organosilicon compound containing mercapto and an acid halide generates the desired blocked mercaptosilane and a metal halide salt, see US Patent no. 6,414,061 whose contents are incorporated herein by reference; but in addition to the previously mentioned difficulties, the organosilicon compounds containing mercapto are expensive making their use prohibitively spread. Thus, there is interest in developing a blocked mercaptosilane that uses a process that is not costly and does not provide the chemical and environmental concerns noted above. There are a variety of known methods for cutting a sulfur-sulfur bond, ie, the use of bases such as amines, phosphines, metal cinnains, metal hydrides and alkali metals, however, metal phosphines and hydrides are expensive and metal cyanides offer a myriad of safety concerns.

BRIEF DESCRIPTION OF THE INVENTION Silicon compounds containing polysulfane are not expensive and widely available, in addition to their supply capacity, the metal halide byproduct does not react with the blocked mercaptosilane product nor do the silicon compounds containing polysulfane have the concerns of a tertiary amine halide salt. The alkali metals are both safe and not expensive. The reaction of an alkali metal with an organosilicon compound containing polysulfane to generate the metal salt of the organosilicon compound containing polysulfane gives the desired acid receptor, in situ, which can be used to produce the blocked mercaptosilane compound and a metal halide salt. Additionally, the use of an aqueous wash of the product thereby minimizes the costs and difficulties mentioned above of removing the metal salt. Removal of metal halide salt by either filtration or by using a centrifuge requires intensive mechanical unit operations and capital investment, while an aqueous wash does not require any but results in a two-phase system , where one phase contains the blocked mercaptosilane and the second phase contains an aqueous solution of the metal halide. The main danger with this method is the potential for hydrolysis of blocked mercaptosilane and for organofunctional silanes. However, through the presence of metal halide, the ionic character of the aqueous phase is increased and therefore minimizes any hydrolysis reaction, see US Pat. 6,294,683. An object of the invention is to provide a process for preparing a blocked mercaptosilane for use as a coupling agent, said process minimizes the production of by-products that react with the blocked mercaptosilane, does not require neutralization or filtration and is commercially available. To keep up with this and other objects of the invention, there is provided a process for the manufacture of a blocked mercaptosilane comprising: (a) reacting at least one organosilicon compound containing poisulphan of the general formula: (R13SiG) 2Sn wherein each R is independently methoxy, ethoxy or alkyl of 1 to about 6 carbon atoms, provided that at least one group R1 is methoxy or ethoxy, G is an alkylene group from 1 to about 12 carbon atoms and n is from 2 to about 8, with at least one alkali metal, alkaline earth metal or a basic derivative of an alkali metal or alkaline earth metal to provide the corresponding metal salt of the organosilicon compound containing poisulphan, and; (b) reacting the metal salt of the organosilicon compound containing poisulphan with an acyl halide or carbonyl dihalide to provide a blocked mercaptosilane. In contrast to the process described in the aforementioned US patent no. 6,414,061, the process of this invention makes it possible to produce a blocked mercaptosilane from readily available organosilicon compounds containing poisulphan. This results in a high purity blocked mercaptosilane which does not require neutralization or filtration to remove the metal halide by-product that is formed upon reaction of the metal salt of the organosium compound containing polysulfane with the acyl halide or carbonyl dihalide. A further objective of this invention is to provide a process that involves the use of an aqueous wash of the final product solution, which unlike the distillation step required in US Patent no. 6,414,061 mentioned above, is a more convenient and efficient way to separate the blocked mercaptosilane product from the metal halide byproduct.

DESCRIPTION OF PREFERRED MODALITIES In the process of this invention, an organosium compound containing polysulfane of the formula (R13SiG) 2Sn, in which R1, G and n have the meanings stated above, and an alkali metal, alkaline earth metal or a strong base derived from the alkali metal or alkaline earth metal, can be considered to react to form a metal salt of the organosium compound containing polysulfane according to the reaction (illustrated for an alkali metal, such as sodium): Metal + (R13SiG) 2Sn > (R13S¡G) 2S-Metal The metal salt of the organosium compound containing poisulphan and a reactive halide, such as an acyl halide or carbonyl dihalide, for example, of the formula R2C (0) X, in which R2 and X have the meanings stated above , can then be considered to react to form the blocked mercaptosilane product and a metal halide byproduct according to the reaction: (R13SiG) 2S-Metal + R2C (0) X R2C (0) SGSiR 3 + Metal-X Useful organosilicon compounds containing polysulfane include, for example, bis [(triethoxysilyl) propyl] polysulfane bis [(m eti Id ytoxy il il) propyl] polysulfane, bis [(triethoxysilyl) isobutyl] polysulfane, bis [(methyl Idioxysilyl) isobutyl] polysulfane, bis [(trimethoxysilyl) propyl] polysulfane, bis [(m eti Id imethoxysilyl) propyl] polysulfane, bis [(trimethoxysilyl) isobutyl] polysulfane, and bis [(methydimethoxysilyl) isobutyl] polysulfane. The organosilicon compound containing polysulfane is reacted with an alkali metal, alkaline earth metal or a strong base derived from an alkali metal or alkaline earth metal. Alkali metals, alkaline earth metals and useful base metal derivatives include, for example, lithium, sodium, potassium, magnesium, calcium, lithium hydride, sodium hydride, potassium hydride, magnesium hydride, calcium hydride, methoxide of sodium, sodium ethoxide, potassium methoxide, potassium ethoxide and mixtures thereof. The metal salt of the organosilicon compound containing the resulting polysulfane is combined with an acyl halide or carbon dihalide, for example, of the general formula R2C (0) X Supra, in which R2 is halogen or alkyl, alkenyl, aryl, alkaryl or aralkyl of up to about 1 8 carbon atoms and X is halogen, to produce a blocked mercaptosilane. Useful acyl halides include acetyl chloride, propanoyl chloride, butanoyl chloride, pentanoyl chloride, hexanoyl chloride, heptanoyl chloride, octanoyl chloride, 2-ethylhexanoyl chloride, lauroyl chloride, oleyl chloride, chloroformate. octyl, adipoyl chloride, phenylacetyl chloride, benzoyl chloride, terephthaloyl chloride and phenyl chloroformate. Useful carbonyl dihalides include carbonyl dichloride (phosgene), diphosgene, triphosgene, thiophosgene, and oxalyl chloride. The blocked mercaptosilane product obtained by the above process confers the general formula R2C (0) SGSiR13, wherein R1, R2 and G have the meanings mentioned above. Specific blocked mercaptosilanes include, for example, 2-triethoxysilyl-1-ethyl thioacetate; 2-trimethoxysilyl-1-ethyl thioacetate; 2- (methyldimethoxysilyl) -l-ethyl thioacetate; 3-trimethoxysilyl-1-propyl thioacetate; triethoxysilylmethyl thioacetate; trimethoxysilylmethyl thioacetate; triopropoxysilylmethyl thioacetate; methyldiethoxysilylmethyl thioacetate; methyldimethoxysilylmethyl thioacetate; methyldiisopropoxysilylmethyl thioacetate; dimethylethoxysilylmethyl thioacetate; dimethylmethoxysilylmethyl thioacetate; dimethylisopropoxysilylmethyl thioacetate; 2-triisopropoxysilyl-1-ethyl thioacetate; 2- (methyldiethoxysilyl) -1-ethyl thioacetate; 2- (methyldiisopropoxysiol) -1-ethyl thioacetate; 2- (dimethylethoxysilyl) -1-ethyl thioacetate; 2- (dimethylmethoxysilyl) -1-ethyl thioacetate; 2- (dimethylisopropoxysilyl) -l-ethyl thioacetate; 3-triethoxysilyl-1-propyl thioacetate; 3-trisopropoxysilyl-1-propyl thioacetate; 3-methyldiethoxysilyl-1-propyl thioacetate; 3-methyldimethoxysilyl-1-propyl thioacetate; 3-methyldiisopropioxysilyl-1-propyl thioacetate; 1- (2-triethoxysilyl-1-ethyl) -4-thioacetylcyclohexane; 1- (2-triethoxy-silhi I-1-ethyl) -3-thioacetylcyclohexane; 2-trietoxysilyl-5-thioacetyl norbornene; 2-triethoxysilyl-4-thioacetyl norbornene; 2- (2-triethoxysilyl-1-ethyl) -5-thioacetyl norbornene; 2-82-triethoxysilyl-1-ethyl) -4-thioacetyl norbornene; 6-triethoxysilyl-1-hexyl thioacetate; 1 -triethoxysilyl-5-hexyl thioacetate; S-triethoxysilyl-1-octyl thioacetate; 1 -triethoxysilyl-7-octyl thioacetate; 6-triethoxysilyl-1-hexyl thioacetate; 1 -triethoxysilyl-5-octyl thioacetate; 8-trimethoxysilyl-1-octyl thioacetate; 1-trimethoxysilyl-7-octyl thioacetate; 10-triethoxysilyl-1 -decyl thioacetate; 1 -triethoxysilyl-9-decyl thioacetate; 1 -triethoxysifl-2-butyl thioacetate; 1 -triethoxysilyl-3-butyl thioacetate; 1 -triethoxysilyl-3-methyl-2-butyl thioacetate; 1 -triethoxysilyl-3-methyl-3-butyl thioacetate; 3-trimethoxysilyl-1-propyl thiooctanoate; 3-triethoxysilyl-1-propyl thiopalmitate; 3-triethoxysilyl-1-propyl thiooctanoate; 3-triethoxysilyl-1-propyl thiobenzoate; 3-triethoxysilypropyl thio-2-ethylhexanoate; 3-methyldiacetoxysilyl-1-propyl thioacetate; 3-triacetoxysilyl-1-propyl thioacetate; and 2-methyldiacetoxysilyl-1-ethyl thioacetate. The reaction of the organosilicon compound containing polysulfane with alkali metal, alkaline earth metal, or basic derivatives of alkali metal or alkaline earth metal, is carried out in mol equivalents from about 1: 1 to about 1: 10, and preferably from about 1: 2.0 to approximately 1: 2.5. The reaction of the metal salt of organosilicon compound containing polysulfane with acyl halide can be carried out in the range from 1.25: 1 to about 1: 1 or with a carbonyldhalide in the range from about 2.25: 1 to approximately 2: 1 mole equivalents. The reaction between the organosilicon compound containing polysulfane and the alkali metal, alkaline earth metal or basic metal derivative is conducted in a range from about room temperature to about the melting temperature of the metal or metal derivative used. Preferably it is conducted at a temperature where the metal used is in a liquid state to increase its surface area such as, for example, from about 25 ° to about 150 ° C and preferably in the range from about 80 ° to about 120 ° C. The subsequent reaction of the metal salt of the organosilicon compound containing polysulfane and acyl halide and carbonium dihalide can be carried out at a temperature from about room temperature to about the boiling point of the solvent used; and preferably the temperature is from about 10 ° to about 50 ° C. The aqueous wash of the blocked mercaptosilane product and the metal halide is conducted in a range from about 4o to about 100 ° C and preferably from about 10 ° to about 50 ° C. In addition, the entire process or any step in it, can be conducted at ambient, elevated or reduced pressure.

The entire process of this invention or any step therein can be conducted in a solvent. Useful solvents may be, for example, any aromatic compound, such as toluene, benzene, xylene and any hydrocarbon solvent, such as hexane, heptane, isooctane and octane. The following examples are illustrative of the process of this invention. All operations were performed under a nitrogen atmosphere. Silquest® A-1589 (bis (triethoxysilylpropyl) disulfane), Silquest® A-15304"more purified disulfide then Silquest® A-1589" (bis (triethoxysilylpropyl) disulfane), Silquest® A-1289 (bis (triethoxysilylproyl) tetrasulane), toluene, and sodium, were used as received without further purification. Deionized water was used as obtained. All GC data are expressed in% mass by weight (w / w) and were obtained from GC Lab using a Hewlett-Packard 5890 Series II gas chromatograph. The following abbreviations and trade names (with their descriptions) appear in the examples: Abbreviation Description CPTES Chloropropyltriethoxysilane MPTES Mercaptopropyltriethoxysilane blocked ercaptosilane 3- (octanoylthio) -1-propyltriethoxysilane ST-BTESPS Bis (triethoxysilyl) propyl sulfone ST-BTESPS Bis (triethoxysilyl) propyldisulfane Si-BTESPS Bis (triethoxysilyl) propyltrisulphane 2Si S-thiocarboxylate mercaptosilane disiloxane Heavy levigados Sum of 2Si and all components that Levigaron after 2Si. Solvent® 140 Mixture of non-aromatic hydrocarbons in the range of C 2 -C 14 with an average molecular weight of 140 COMPARATIVE EXAMPLE 1 515.20 g of toluene were treated at room temperature with 25.00 g of sodium (1.076 mols) and heated to ~ 105 ° C. The molten sodium-toluene suspension was treated with 265.21 g of MPTES (1.079 moles) over the course of 30 minutes, resulting in the emission of hydrogen. After the addition of MPTES was completed, the resulting clear, colorless solution was cooled to ~ 45 ° C and treated with 164.75 g of octanoyl chloride (0.982 mol). The addition of octanoyl chloride resulted in an exothermic reaction and the generation of salts. The octanoyl chloride was added over the course of one hour while the reaction temperature slowly increased to 62 ° C. Once the reaction was cooled to 50 ° C, 215.0 g of deionized water was added resulting in the dissolution of the salts and the formation of two layers. The aqueous layer was removed and the toluene was removed, under vacuum, recovering 504.72 g of toluene (98% recovery). 387.59 g of blocked mercaptosilane was recovered as a clear, colorless liquid with the following GC composition (98% efficiency): Levigado Blocked Toluene Ethyl Octanoate CPTES MPTES Mercaptosilane Si-BTESPS 2Sj Heavy 0. 45 0.74 0.01 4.67 89.74 0.85 1.71 3.49 COMPARATIVE EXAMPLE 2 At room temperature, a 50 I reactor was charged with 20.4 kg of toluene followed by the addition of 1015 g of sodium (43.7 moles). This suspension was heated to ~105 ° C and the resulting molten sodium was treated with 11.0 kg of MPTES (44.8 moles) during the course of one hour and 22 minutes, resulting in the emission of hydrogen. After the addition of MPTES was completed, the clear solution was cooled to room temperature and then treated with 7.0 kg of octanoyl chloride (42.8 moles) over the course of one hour and 35 minutes with the reaction temperature reaching 58 °. C. The resulting mixture was cooled to 32 ° C and then 8.6 kg of deionized water were added resulting in the dissolution of salts to give two layers. The aqueous layer was removed, recovering 11.5 kg of aqueous waste and the toluene was removed under vacuum recovering 20.9 kg of toluene (102% recovery). The product was filtered through a Kuno filter using a 5 micron filter pad, recovering 14.0 kg of blocked mercaptosilane as a clear yellow liquid with the following GC analysis (85% efficiency): Blocked Levigado Tolueno Ethyl Octanoate CPTES MPTES Mercaptosilane SRBTESPS 2Si Heavy 0. 69 3.80 0.01 6.40 82.04 0.71 2.28 2.97 EXAMPLE 1 At room temperature, 526.82 g of toluene were treated with 29.28 g of sodium (1.261 mol) and heated to ~ 10 ° C. The molten sodium-toluene suspension was treated with 299.1 g of Silquest® A-1589 (0.590 mol) over the course of 45 minutes. The addition of Silquest® A-1589 was exothermic and an opaque, dark red-purple solution was formed. After the addition of Silquest® A-1589 was completed, the reaction mixture was cooled to ~ 45 ° C and 1.89.26 g of octanoyl chloride (1152 moles) were added over the course of one hour, resulting in a suspension of viscous salt with the reaction reaching 60 ° C. At ~ 45 ° C, the reaction was treated with 278.42 of water resulting in the dissolution of the salts to give a transparent yellow-orange toluene layer and an opaque, dark aqueous layer, which was removed. 382.65 g of aqueous waste were recovered. The toluene was extracted in vacuo recovering 576.93 g of toluene (106% recovery, contained water). 373.53 g of blocked mercaptosilane was recovered as a dark orange liquid, transparent with the following GC analysis (87% efficiency): Etylide Blocked Levgado Tolue- Oda- CPTES MPTES Mercarte- Si-BTESPS SrBTESPS SrBTESPS 2Si Pesa-n noato silano dos 1. 41 0.76 0.01 0.43 80.36 6.80 4.97 0.01 2.90 4.06 EXAMPLE 2 At room temperature, a 50 I reactor was charged with 20.9 kg of toluene followed by the addition of 164 g of sodium (45.8 moles) and heating to ~1 1 0 ° C. The molten sodium was treated with 1 0.3 kg of Silquest® A-1 589 over the course of 69 minutes resulting in an exothermic reaction. After the addition of Silquest® A-1 589 was completed, the resulting dark suspension was cooled to ~ 38 ° C and then treated with 6.3 kg of octanoyl chloride (38.1 moles) over the course of two hours with the Reaction temperature reaching 48 ° C. The resulting suspension was cooled to room temperature and then treated with 0.01 kg of deionized water. An exotherm of 5 ° C was observed and the salts dissolved resulting in two layers. The dark opaque aqueous layer was removed by recovering 14.2 kg of aqueous waste. The toluene was extracted recovering 1 9.9 kg (95% recovery). The product was filtered through a filter one using a 5 micron filter cushion, recovering 14.1 kg of gassed mercaptosilane as a clear yellow liquid with the following GC analysis (92% efficiency): Locked Etilo Levigado Tolue- Oda- CFTES MPTES ercapto- Sj-BTESPS ST-BTESPS SrBTESPS 2Si Pesa-ng noato silane two 0.80 0.99 0.01 1.00 79.01 7.08 5.72 0.16 2.36 4.02 EXAMPLE 3 At room temperature, 509.88 g of toluene were treated with 30.04 g of sodium, (1.299 moles) and heated to -110 ° C. The molten sodium-toluene suspension was treated with 300.97 g of Silquest® Y-1 5304 (0.590 mol) over the course of 45 minutes. The addition of Silquest® Y-15304 was exothermic and an opaque, red-purple opaque solution was formed. After the addition of Silquest® Y-1 5304 was com- pleted, the reaction mixture was cooled to ~ 45 ° C and 196.01 g of octanoyl chloride (1.1-69 mols) were added during the course of a hour resulting in a viscous salt suspension with the reaction reaching 60 ° C. At ~ 45 ° C, the reaction was treated with 270.72 g of water resulting in the salts which are dissolved to give a clear orange-yellow toluene layer and an opaque, dark aqueous layer, which was removed. 330.89 g of aqueous waste were recovered. The toluene was extracted under vacuum recovering 382.98 g of toluene (75% recovery). 433.06 g of blocked mercaptosilane were recovered as a dark yellow, transparent liquid, with the following GC analysis (95% efficiency): Locked Etilo Levigado Tolue- Oda- CPTES MPTES Mercarte- SrBTESPS ST-BTESPS SrBTESPS 2Si Pesa-ng noato silano dos 0. 04 0.46 0.01 0.015 84.47 2.15 5.41 1.52 3.02 4.91 EXEM PLO 4 At room temperature, a 50 l reactor was charged with 20.4 kg and 1061 g (45.7 mol) and heated to 1110 ° C. The molten sodium was treated with 1 0.3 kg of Silq uest® Y-1 5304 over the course of 69 minutes resulting in an exothermic reaction. After the addition of Silquest® Y-1 5304 was completed, the resulting dark opaque suspension was cooled to 35 ° C and 6.2 kg of octanoyl chloride (37.6 moles) were added over the course of one hour and 49 minutes, resulting in in an exothermic reaction with the reaction temperature reaching ~ 50 ° C. After the addition of octanoyl chloride was completed, the resulting suspension was treated with 10.1 kg of deionized water, resulting in salts that are dissolved to give two layers. The resulting dark aqueous layer was removed, recovering 13.7 kg. The toluene was removed under vacuum, recovering 20.7 kg (1 02% recovery). The product was filtered through a Kuno filter using a 5 micron filter pad recovering 13.9 kg of blocked mercaptosiiano as a transparent dark yellow liquid with the following GC analysis (92% efficiency): Locked Etilo Levigado Tolue- Oda- CPTES PTES Mercapto- SrBTESPS &-B7ESPS ¾BTESPS 2Si Pesa-ng noato silane two 0. 61 0.82 0.01 2.72 82.04 2.57 6.57 0.14 238 3.37 EXAMPLE 5 At room temperature, 1 60 g of Solvent® 140 were treated with 1 1 g of sodium (0.478 mol) and heated to ~ 10 ° C. The Solvent® 140-molten sodium suspension was treated with 63 g of Silquest® A-1289 (0.1 1 7 moles) over the course of 45 minutes. The addition of Silquest® A-1289 was exothermic and an opaque, dark red-purple solution was formed. After the addition of Silquest® A-1289 was completed, the reaction mixture was cooled to ~ 45 ° C and 76 g of octanoyl chloride (0.468 moles) were added over the course of one hour, resulting in a suspension of viscous salt with the reaction temperature reaching 104 ° C. At ~ 45 ° C, the reaction was treated with 175 g of water, resulting in the dissolution of salts to give a transparent orange-yellow Solvent® 140 layer, and an opaque, dark aqueous layer, which was subsequently removed. 236 g of aqueous waste were recovered. The toluene was removed in vacuo recovering 155 g of Solvent® 140 (97% recovery). 110 g of blocked mercaptosilane was recovered as a dark yellow liquid, transparent with the following GC analysis (89% efficiency): Locked Etilo Levigado Tolue- Oda- CRÍES PTES ercapto- SrBTESPS ST-BTESPS SrBTESPS 2Si Pesa-no noato silano dos 0.70 2.20 0.01 2.66 64.75 0.90 23.31 2.18

Claims

CLAIMS 1 . A process for the manufacture of a blocked mercaptosilane comprising: reacting at least one organosilicon compound containing poisulphan of the general formula: (R13SiG) 2Sn (a) in which each R1 is independently methoxy, ethoxy or alkyl from 1 to about 6 carbon atoms, provided that at least one group R 1 is methoxy or ethoxy, G is an alkylene group from 1 to about 12 carbon atoms and n is from 2 nasa about 8, with at least one metal alalino, alkaline earth metal or a basic derivative of an alkali metal or alkaline earth metal to provide the metal salt corresponding to the organosilicon compound containing poisulphan, and; (b) reacting the metal salt with the organosilicon compound containing poisulphan with an acyl halide or carbonyl dihalide to provide a blocked mercaptosilane. 2. The process of claim 1, wherein the organosilicon compound containing poisulphan is selected from the group consisting of bis [(thio-toxysilyl) propyl] poly-sulfane, bis [(methyldiethoxysilyl) propyl] polysulfane, bis [( triethoxysilyl) isobutyl] poisulphane, bis [(methide) isobutyl) isobutyl] poisulphan, bis [(trimethoxysilyl) propyl] polysulfane, bis [(methi Id imethoxysilyl) propyl] poisulphan, bis [(trimethoxysilyl) isobutyl] polysulfane, and bis [(methyldimethoxy-1-yl) isobutyl] poly-sulfane. 3. The process of claim 1, wherein the alkali metal, alkaline earth metal and basic alkali metal or alkaline earth metal derivatives are selected from the group consisting of lithium, sodium, potassium, magnesium, calcium, hydride lithium, sodium hydride, potassium hydride, magnesium hydride, calcium hydride and mixtures thereof. 4. The process of claim 1, wherein the acyl halide or carbonyl dihalide is of the general formula: R2C (0) X wherein R 2 is halogen or alkyl, alkenyl, aryl, alkaryl or aralkyl of up to about 18 carbon atoms and X is halogen. The process of claim 4, wherein the acyl halide is acetyl chloride, propanoyl chloride, butanoyl chloride, pentanoyl chloride, hexanoyl chloride, heptanoyl chloride, octanoyl chloride, 2-ethylhexanoyl chloride, lauroyl chloride, oleyl chloride, octyl chloroformate, adipoyl chloride, phenylacetyl chloride, benzoyl chloride, terephthaloyl chloride and phenyl chloroformate. The process of claim 4, wherein the carbonyl dihalide is phosgene, diphosgene, triphosgene, thiophosgene, and oxalyl chloride. The process of claim 4, wherein the blocked mercaptosilane product is of the general formula: R2C (0) SGHSiR13 wherein R, R2 and G have the meanings mentioned above. The process of claim 7, wherein the blocked mercaptosilane product is selected from the group consisting of 2-triethoxysilyl-1-ethyl thioacetate; 2-trimethoxylalkyl-1-ethyl thioacetate; 2- (methyldimethoxy) -1-ethyl thioacetate; 3-trimethoxysilyl-1-propyl thioacetate; triethoxymethylmethyl thioacetate; trimethoxysilylmethyl thioacetate; triisopropoxymethylmethyl thioacetate; methyldiethoxysilylmethyl thioacetate; methyldimethoxysilylmethyl thioacetate; methyldiisopropoxysilylmethyl thioacetate; dimethylethoxysilylmethyl thioacetate; dimethylmethoxysilylmethyl thioacetate; dimethylisopropoxysilylmethyl thioacetate; 2-triisopropoxysilyl-1-ethyl thioacetate; 2- (Methyldiethoxysilyl-1-ethyl) thioacetate; 2- (Methylidepopropoxysilyl) -1-ethyl thioacetate; 2- (dimethylethoxysilyl) -l-ethyl thioacetate; 2- (dimethylmethoxysilyl) -1-ethyl thioacetate; - (dimethylisopropoxysilyl) -1-ethyl, 3-triethoxy-1-propyl thioacetate, 3-triisopropoxysilyl-1-propyl thioacetate, 3-methyldiethoxysilyl-1-propyl thioacetate, 3-methyldimethoxysilyl-1-propyl thioacetate, thioacetate. of 3-methydiisopropoxysilyl-1-propyl; 1- (2-triethoxysilyl-1-ethyl) -4-thioacetylcyclohexane; 1- (2-triethoxysilyl-1-ethyl) -3-thioacetylcyclohexane; 2-triethoxysilyl-5-thioacetyl norbornene; 2-triethoxysilyl-4-thioacetyl norbornene; 2- (2-triethoxysilyl-2-ethyl) -5-thioacetyl norbornene; 2- (2-triethoxysilyl-1-ethyl) -4-thioacetyl norbornene; 6-triethoxysilyl-1 -hexyl thioacetate; 1 -triethoxysilyl-5-hexyl thioacetate; 8-triethoxysilyl-1-octyl thioacetate; 1 -triethoxysilyl-7-octyl thioacetate; 6-triethoxysilyl-1-hexyl thioacetate; 1 -triethoxysilyl-5-octyl thioacetate; 8-trimethoxysilyl-1-octyl thioacetate; 1-trimethoxysilyl-7-octyl thioacetate; 1-triethoxysilyl-1 -decyl thioacetate; 1-triethoxysilyl-9-decyl thioacetate; 1 -triethoxysilyl-2-butyl thioacetate; 1 -triethoxysilyl-3-butyl thioacetate; 1 -triethoxysilyl-3-methyl-2-butyl thioacetate; 1 -triethoxysilyl-3-methyl-3-butyl thioacetate; 3-trimethoxysilyl-1-propyl thiooctanoate; 3-triethoxysilyl-1-propyl thiopalmitate; 3-triethoxysilyl-1-propyl thiooctanoate; 3-triethoxysilyl-1-propyl thiobenzoate; 3-triethoxyl-1-propyl thio-2-ethylhexanoate; 3-methyldiacetoxysilyl-1-propyl thioacetate; 3-triacetoxysilyl-1-propyl thioacetate; and 2-methyloxy-acetoxysilyl-1-ethyl thioacetate. 9. The process of claim 1, wherein the range of mol equivalents of alkali metal, alkaline earth metal, basic alkali metal or alkaline earth metal derivative to polysulfane containing organosilicon compound is from about 1: 1 to about 10: 1 , and preferably from 2: 1 to 2.5: 1. The process of claim 1, wherein the range of metal salt of organosilicon compound containing polysulfane to acyl halide is from about 1.25: 1 to about 1: 1 mol equivalents or carbonyl dihalide is from about 2.25: 1 to about 2: 1 mole equivalents. eleven . The process of claim 1, wherein the reaction between the organosilicon compound containing polysulfane and the alkali metal, alkaline earth metal or a basic derivative of alkali metal or alkaline earth metal is conducted at a temperature at which the metal or metal derivative is in the liquid state. The process of claim 1, wherein the reaction of the metal salt of organosilicon compound containing polysulfane and the acyl halide or carbonyl dihalide is conducted at a temperature of from about 10 ° to about 50 ° C. 13. The process of claim 1 conducted in a solvent. 14. The process of claim 13, wherein the solvent is selected from the group consisting of toluene, benzene, xylene, hexane, heptane, octane and octane. SUMMARY A process for the manufacture of a blocked mercaptosilane comprising: reacting at least one organic silicon compound containing poisulphan of the general formula: (R13SiG) 2Sn (a) wherein each R1 is independently methoxy, ethoxy or alkyl of 1 to about 6 carbon atoms, provided that at least one group R 1 is methoxy or ethoxy, G is an alkylene group of 1 to about 12 carbon atoms and n is 2 to about 8, with at least one alkali metal, alkaline earth metal or a basic derivative of an alkali metal or alkaline earth metal to provide the corresponding metal salt of the organic silicon compound containing poisulphan, and (b) reacting the metal salt of the organic silicon compound containing poisulphan with an acyl halide or dihalide carbonyl to provide a blocked mercaptosilane.